LEDs offer benefits over incandescent and fluorescent lights as sources of illumination. Such benefits include high energy efficiency and longevity. To produce a given output of light, LEDs consume less electricity than incandescent or fluorescent lights. Additionally, on average, LEDs last longer than incandescent or fluorescent lights before failing.
The level of light a typical LED outputs depends upon the amount of electrical current supplied to the LED and upon the operating temperature of the LED. That is, the intensity of light emitted by the LED changes according to electrical current and LED temperature. Operating temperature also impacts the usable lifetime of LEDs.
As a byproduct of converting electricity into light, LEDs generate heat and raise the operating temperature, resulting in efficiency degradation and premature failure. Typically, a heat management system, such as a heat sink, is used in conjunction with the LEDs to facilitate maintenance of proper LED operating temperatures. Conventional LED-based recessed luminaires include a housing and a conventional LED module that is coupled within the housing. The conventional LED module includes a heat sink, a fastening device for facilitating coupling between the conventional LED module and the housing, and one or more LEDs. The housing includes a cavity formed therein and an opening at one end. The housing is installed within and above an aperture formed in a support structure, such as a ceiling, and oriented such that the opening faces a desired illumination area, such as a room. Typically, a space is formed around and between the lower exterior portion of the housing and the perimeter of the aperture. The opening is positioned in substantially the same plane as a lower surface of the support structure; however, the opening can be positioned in a different plane, such as slightly above the lower surface of the support structure.
The heat sink is installed and fitted within the cavity of the housing, generally using one or more fastening devices, such as torsion springs, and substantially occupies the entirety of the diameter of the cavity to maximize its heat removal performance. The conventional LED module is designed to fit within a housing having an opening with a certain nominal diameter. For example, one conventional LED module is designed to fit within a housing having a six inch nominal diameter opening, while a different conventional LED module is designed to fit within a different housing having a five inch nominal diameter opening. Thus, the conventional LED module typically is not designed to flexibly fit within housings having differently sized nominal diameter openings. The LEDs are typically coupled to a substrate, which is in thermal communication with the heat sink. The LEDs emit light and are oriented in a manner such that the light is directed to the desired illumination area through the opening.
Conventional LED-based recessed luminaires can also include a trim ring. The trim ring is positioned adjacent to the opening and covers the opening. The trim ring typically is separably coupled to the heat sink or to a portion of the housing, generally by use of torsion springs, and is positioned so that at least a portion of the trim ring extends below the support structure and covers the space formed between the lower exterior portion of the housing and the support structure when viewed from an area below the support structure. The trim ring is thermally coupled to the heat sink; however, since the trim ring is separably coupled to either the heat sink or the housing, the amount of heat removal from the trim ring into the area below the support structure, or room area, is limited because the area of direct contact between the trim ring and the heat sink is reduced. Some conventional LED-based recessed luminaires also include a reflector. The reflector typically is separably disposed within the heat sink and surrounds the LEDs. The reflector directs light emitted from the LEDs toward the opening. Conventional LED-based recessed luminaires having several separably coupled components increase costs related to tooling costs and assembly costs.